Domestic water supply systems are usually connected to the water company's main by a service pipe, in two parts, the water company's pipe making an end to end junction with the customer's pipe at the highway boundary. A major public health problem remains the large number of premises which are still equipped with lead pipes, as the slightly soluble lead is a well known cumulative poison. One approach to this problem has been to replace lead piping with polyethylene plastics tubing. Alternative ductile metals such as copper have their own cumulative hazards.
As an alternative to replacement of lead pipes, it has been proposed to line the pipes with a polyethylene film which is everted by fluid pressure into the pipe (see WO97/04269) or a polyethyleneterephtalate (PET) film which is extruded as a profile and inflated by fluid pressure when heated in situ. This presses the lining against the inner walls of the pipe, and softens the lining to achieve a measure of thermal bonding to the pipe wall.
The known techniques all involve significant investment in capital plant and equipment, including those outlined above and also the use of impact moles (usable in compactable soils but not capable of being steered around obstructions such as other utility conduits gas, sewage, electricity, etc. . . ), pipe pulling, pipe splitting, guided drilling, pipe pushing, narrow trenching rods and powerful vacuum excavators.